Lithiated transition metal phosphates such as LiFePO4, including various doped and modified versions thereof, are finding growing utility as cathode materials for lithium batteries. Such materials are disclosed in U.S. Pat. Nos. 6,730,281; 6,855,273; and 6,514,640; as well as in published U.S. Application 2004/0086445, among others. Such materials have a very good capacity for lithium ions; and while they have reasonably good ionic conductivity, they have relatively low electron conductivities, and this factor has limited their efficiency and utility. Hence, various efforts have been undertaken to dope, modify, or otherwise supplement such materials to enhance their electrical and/or ionic conductivity.
As will be explained hereinbelow, the present invention provides a composite material based upon lithiated metal phosphates which material combines good electrical conductivity with high lithium ion capacity and conductivity. The materials of the present invention are simple and economical to synthesize, and have very good utility as cathodes for lithium batteries.